The present application relates to determining a position of an object. More specifically, the present disclosure relates to methods and systems for accurately determining a position and a pose of a robotic system or end effectors associated with such a robotic system.
Various techniques are available for determining the position of an object, robotic or otherwise. For example, a global positioning system (GPS) uses precise clocks on-board orbiting satellites to provide points for ground-based multi-lateration of a particular object, having an accuracy of approximately 3 meters. Such positioning systems require direct signal reception from satellites, making them inappropriate for indoor or select outdoor situations where direct signal reception from a satellite is impossible to establish or maintain over an extended period of time.
Techniques to improve accuracy of GPS signals, such as differential or real-time kinematic (RTK) methods, are too expensive for the price point of most commercial robots such as cleaning robots or inventory control robots. Other techniques such as radio frequency (RF) receiver signal strength indication can be used indoors, but are only accurate to a few meters which may be too inaccurate for specific applications. With such uncertainty in basic location determination, the use of current location-based techniques from which to derive orientation or pose of a robot or its end effectors are ineffective.
The introduction of ultra-wideband (UWB) signaling techniques with timing accuracy to a fraction of a nanosecond and range accuracy to within a few centimeters offers the opportunity to use a relative positioning system in a coordinated fashion to establish the orientation and/or the pose of a robot or of an end effector that may not be rigidly coordinated with the basic robotic orientation.
However, various prior analysis and techniques for determining position using UWB signals require that the precise position of any reference objects or anchors be fully known beforehand, e.g., in a laboratory environment. Further, the scope of the prior UWB signal approaches is limited to the objective of using ranging to determine the location of a single point in space, rather than a full description of, for example, a robot location and pose.
In real-time location determinations, such requirements do not cover the practical applications of establishing UWB ranging-based reference frames, and do not reflect determinations of a robot position and pose without additional types of sensors (e.g., non-UWB based). Furthermore, map generation for a specific area based upon measuring locational information related to a moving robot fails to establish a relationship between generated maps to the actual UWB reference frames. Similarly, the map generation fails to describe the use of digital map features to include characteristics that could influence command of the robotic pose such as specific poses a robot should take in relation to a specific object located within the generated map. Additionally, prior techniques have generally been restricted to co-planar objects that do not require more complex three-dimensional location sensing, estimating or pose determination.